In my experience, the Merlins work quite well with tube amps. They prefer an amplifier with a fairly low damping factor (fairly high output impedance). Solid state amps with damping factors over 200 or so tend to have an overly lean tonal balance with the Merlins. This is a generalization, of course.
In addition to Joule Electra, the Merlins sound quite good with Atma-Sphere amps - another OTL. Many Merlin owners are using Berning amps, a quasi-OTL. I would imagine that a large SET (using an 845 or 211 class output tube) would also sound very good with the Merlins. DeHavilland makes some very nice high-power SET's.
The Merlins are extraordinary loudspeakers - superb articulation and resolution, holographic imaging, and a very lively and boxless presentation. Match 'em with the right amps and position 'em well, and you're done.
Duke
Disclaimer - I peddle Atma-Sphere amps, but don't sell any of the other stuff mentioned here.
